Air conditioning device



Feb. 15, 1938.

R. 1 DREW ET AL AIR CONDITIONING DIIvIcIl:-

Fild May 18, 19:55

am ma? Patented Feb. 15, 1938 n UNITED STATES PATENT/OFFICE am coNDrnoNiNG DEVICE Ralph L. Drew, North'llymouth, and Stephen A. Reed, Duxbury, Mass., assignors to Plymouth Cordage Company, North Pvmouth, Mass., a corporation of Massachusetts Application May 1s, 1935, sei-inno. 22,206 1o claims. (ci. iss-49) This invention relates to improvements in air vantages of low inertia, low cost, efficiency, and,

conditioning devices. v

More especially it relates to air flltering units, The invention provides these and other adand particularly to the type wherein material of vantageous results by employing in each unit a 5 fibrous nature constitutes the filtering medium. plurality of relatively thin layers of loosely as- The invention provides improvements whereby sociated fibre or other lamentary material, and

a fibrous medium may be sustained and main-A by combining them with spacing elements which tained with approximate uniformity of distribuhold those layers apart and so make spaces betionand filtering effect at all points across-the tween the layers, across which the air iiows with full area of cross-section through which the air less velocity than through the fine passages 1o is flowing; and wherein the combination of relaamong fibres. Some of the suspended dust is thus tively thin sheets of the ltering medium with allowed to settle, and so becomes removed by'bematerial providing intervening spaces produces ing deposited in the intervening free areas, inimportant advantages as regards uniformity of stead of all of it having to cling to the fibrous filtering results, and as regards efliciency over material,inwhose passages it has clogging effect. 15 longer periods of use, as compared with prior art The nbre layers thus spaced apart may be devices of the same general sort. arranged in a holder adapted toA be set across an It has been heretofore proposed to arrange air-flow passage as a. iiltering unit. The holder loosely matted material of brous nature in the may have a channelled frame, as a retainer for 2'0 ow path of air, thus to arrest oating subthe edges of the associated fibre layers, andrhave 20 stances, for the air to pass on in a more wholeopenwork front and rear faces, in the nature of some condition. Various materials have been s. proposed for such a filtering medium, such as The desired initial looseness of mutual associasteel wool, spun glass, hair, and other laments. tion of the fibres may be attained, and may be But problems remain unsolved, because the maintained through the life of the filtering unit, 25 fibrous material shifts its position and becomes by spraying an adhesive liquid on the interior compacted, and because the air passages through surfaces of the box-like holder, and also on the the filtering mass become filled at their surface separators if desired, by means of which the entrances, after a relatively short period of use, brous layers become effectively securedinproper so as to interfere with the desired flow of air, and relation to the holder, and resist the tendency to 30 to affect the uniformity and the eflicacy and the be compacted by the air flow. efficiency of filtering. Vibration causes a sagging In a. preferred form of the invention provision and edgewise compacting, which blocks some is made for the impaling of the fibrous layers parts of the filter, and opens others where air on the separators; and this may be either incan pass freely without being filtered. stead of or in addition to the said adhesion. This 35 One object of the invention is to make filtering impaling when .distributed over the whole cross- `units w 'ch can be more durably effective and section of air iiow, in a filter frame standing on efcient, edge, prevents sagging of the filtering medium `In addition to this, the invention provides imtoward one side of the air passage,y as a result of 40 provement in the action, in that it provides for vibration or for other reasons. The permanent 40 changing the pace of air along its course through success of these measures is promoted by combinthe filtering unit, and thereby removes an ining therewith a brous material having a low creased percentage of its floating matter. It does specific gravity, of which the long and hard this with a reduced body of filtering material. vegetable fibres such as sisal, java and manila Also it provides dust collecting air chambers are examples, as the filaments of material such 45 within the unit. asthis are long and rm enough to span the It is a further feature to do these things with supports and have negligible inertia and momeninexpensive, single service holding appliances,` tum, attributes which coact favorably toward the each having the double merit that it requires attaining of permanence of structure in the presonly a fractional filling of the filtering medium ence of incessant vibration. 50 for a full charge; and that it may be discarded It is intended that the patent shall cover, by with the said medium after its period of useful suitable expression in the appended claims, whatservice. If preferred, the holder may be of a ever features of patentable novelty exist in the permanent type, reflllable. The medium itself invention disclosed.

may be hard vegetable bre, which has the ad- However, the scope is not limited to the specific 55 devices which are selected for portrayal as illusing or holder, and with 'apart within the unit.

trative embodiments.

In the accompanying drawing:

Figure 1 is an isometric view of a filtering unit embodying features of the invention, with the front face indicated only inpart, and with a portion of the unit broken away to cross sections parallel with the face at successive stages of dls' tance therefrom;

Figure 2 is an elevation, on a larger scale, of a. corner fragment, with the outer portion of the box holder removed;

Figure 3 is an elevation, on a larger scale, in

section on 3-3 of Figure l;

Figure 4 is an isometric view of a fragment of one of the separator elements;

Figure 5 is an elevation, in section. of a fragment of a nlter unit with a modified form of casa dinerent way of embodying the spacing device between nbre pads; and.

Figure 6 shows similarly another embodiment of spacing device.

'I'he drawing portrays a nltering unit of a type suitable for use under a variety of conditions and in various locations where nltration of airmay be desirable. It is especially suited for use in Pullman and other railroad cars, where dust and soot are prevalent, and where the enlciency and durability of filtering units heretofore have suifered from the almost continuous vibration to which they are subject. A

According to the invention the nlter has a plurality of rlayers I f of nbre, set normal to the direction of air flow through the unit, and spaced Each layer I I constitutes a solids-screening section organized as a sheetform mass. Any usual or suitable nbre or nbrelike material may be employed as the nltering medium, but hard vegetable nbre combines well for the purposes in hand, each layer being arranged in several veils of the nbre, deposited loosely, one upon the other, to the desired thickness. Three such layers I0 are represented in Figure 3, mounted in a r-casing I2 which may be of metal or cardboar y and rear faces are foraminous, being of openwork grid construction as seen at I4, I6.

{craters-I8, which also may be of metal or cardness of the grid, intervening between adjoining layers I0' of nbre, constitutes a sheet-form solids-settling section which by blocked into a multiplicity of rectangular areas. being contiguous sub-chambers,

multiplying of these across the airnow area makes it so that a particle-'of dust,

floating at the axis or at the very top of the air stream, can be caught,-for upon settling but a short distance it reaches a noor where it can rest. The said crossed elements of the separators provide struts, distributed over the whole area across the airnow, for maintaining the nbre against serious displacement from its initial uniform distribution across the air now. 'Ihe relatively thin dimension of individual layers tends to minimize the compacting of the nbre. In the case illus- Said grid. is-

2,1os,ass

trated the unit represented may be considered to be two inches thick, one-half of which is two halfinch spaces, so that each nbre pad illustrated would be only about one-third of an inch in thickness. The open space.acting as a honeycomb bailiings of air passing through a brous layer Il. The chamber space therefore provides a Illzatter is arrested among the nbres of the layers The making of the nlter so that, when it is in service, its eifectiveneas and its eiliciency, for n1- tering, will be maintained throughout the full cross sectional area of the unit are two important attributes of the invention. This is particularly important in installations subject to vibration or shock; and it is attained by either or all of three devices: impaling means for the nbre; stiffening means dlierefor; and adhering means therefor. ,f

Any reasonably sharp elements or projections on the separators I8 will be sunicient for the imtinuous pressure of these devices save the individual layers I0 from becoming seriously compacted. 'I'he surface, or all layers, may be treated with a compound, thus rendering .the whole nre resisting. As examples of the practice of the invention in utilizing nlamentary material for the this way, the first layer I0 may permit the passing of some of the medium-fine and fine particles in the air, and they may be caught in a later layer. Clogging of the entrance spaces by a building up of deposits of fine material is thus delayed, and that ne material is distributed throughout the unit. But the first layer I0 predominantly stops relatively coarse foreign substances; the mid-layer III intercepts some of the finer foreign matter; and the third layer I0 is so dense as effectively to lter out the finest particles which may have continued in the air to this' stage. The eiciency is increased in this respect by spraying the fibre with a heated liquid or a solution which cools or evaporates so as to leave a tacky dust-catching surface. This may at choice be applied in varying degrees of tacklness. An illustration of such, applied when heat.- ed, is petroleum jelly.

In Figure 3, this gradation of filtering effect is portrayed by variation in the density of the respective layers I0. This can be accomplished with precision by building up the filter .pads og hard fibre carded into thin veils, several veils being put together to make a single pad. By varying the number assembled for a pad, but ultimately compressing the assembly to the dimension of thickness predetermined for the pads, variations of size of air passages result.

If desired, successive veils may have their flbres predominantly crossing each other, thereby to produce a criss-cross arrangement of bres in the ultimate pad, which tends toward a greater uniformity of filtering effectthan when the fibres are predominantly in approximate parallelism.

If the casing or box l2 is an inexpensive cardboard or metal container as represented in Figures l-3, it may be discarded with the filter material after the latter has become covered or choked. Ii a rellable container be employed, it may take the form of a channel frame 32 as indicated in Figure 5, the front and rear grids 34, 36, being of metal or any other suitable material. In either case, as represented, the parts may be secured together in any desired way, the ties 38 being one way that is both practicable and convenient.

The grid illustrated in Figure l can be recognized as one variety of any coarse filling, maintaining space between adjacent lter pads. This spacing-filling is not necessarily symmetrically organized; and there is observable advantage even when the grid construction which provides multilevels of chamber-floors is omitted. The spacing material may be any suiiiciently stiff aggregate of filamentary form; and Figure 5 illustrates an embodiment of the spacing device which is a sheet of coarse-meshed fine wire 38 or screening of any inexpensive type, as chicken wire, folded into corrugations which reach across the space between adjacent pads. 'I'he crests of the corrugations constitute supports for the fibres in the pads, and may engage them at frequent intervals both by impaling points (not shown, but which may be provided by cutting and bending out wires) or by pressure of the wires, and by adhesion of a glue. Similarly the support may be such a meshed wire 40 arranged in a plane on the face of a bre pad, as in Figure 6.

We claim as our invention:

l. An air filtering unit comprising a container having openwork front and rear faces; filtering contents therefor comprising a flat mat of loosely associated hard vegetable fibres; and an interior grid, crossing the container beside a face ci the mat, and pressing against the fibres at said face, having thin strips of substantial breadth set edgewise in the direction of air flow, crossing each other and halved together.

2. An air filtering unit comprising a container having openwork front and rear faces; filtering contents therefor comprising a flat mat of loosely associated hard vegetable fibres; and supports for the fibre, extending beside a face of the mat, transversely of the direction of air ow through the unit, comprising thin strips of substantial breath set edgewise in the said direction of air flow and pressing against the fibres at said face of the mat.

3. An air filtering unit comprising a container having face and back open for air flow, adapted to be set in a conduit of air flow; a plurality of mats therein, of loosely associated hard vegetable fibres; a separator extending between side Walls across the container, transversely to the-v direction of air ow, spacing said mats apart in the direction of flow through the unit; and projecting points on the separator, distributively positioned over the area thereof, for engaging in surface parts of the mass of fibre, thereby to maintain the distribution of the fibre within its mat; the separator having broad thin strips, set edgewise to the direction of air now and in whose edges are recesses into which fibres pressed edgewise against the strips can enter, the said projecting points being in pairs at the entrances of the recesses, one on each side of a recess, extending in approximate parallelism with the general direction of the edge in which the recess is.

4. An air filtering unit comprising three blocks of loosely associated hard vegetable fibres, said blocks having broad front and back surfaces, to which the air flow is normal, and being set parallel, in succession, in the unit, in the direction of air ow; edgewise strips, criss-crossed over each other, providing spaces between each two adjacent blocks, each space having length in direction of air ilow exceeding the thickness of fibre blocks, in direction of air flow through the unit; said unit having exterior front and back face grids; and ties at intervals between the grids.

5. A filter for removing solids from a gas stream, comprising a chamber-casing having foraminous front and back faces and containing a solids-settling section between two solidsscreening sections, the whole being combined as a unit adapted to stand vertically and removably across a gas duct; the said screening sections being sheet-form masses of bres loosely assembled together; and the said settling section being a sheet-form succession of contiguous subchambers, into which this part o-f the main chamber is divided, constituted by thin strips having width several times as great as their thickness, set edgewise and perpendicular to the faces of the screening sections and holding the screening sections apart; some of the said partitions constituting iloors at locations distributed across the height of the settling section, thereby arresting solids which settle a short distance from any level in this part of the main chamber and others of the said partitions constituting supports preventing sagging of the said floors.

6. An air filter unit, comprising fibrous filtering material organized in a plurality of masses of fibre in the shape of blocks, in each of which blocks the fibres extend across the direction of flow of air through the unit, and are loosely matted to a substantial thickness of block in the said direction of flow of air; means for maintaining the blocks spaced aparta substantial distance in the said direction of fiowof air, said means comprising thin sheet elements set edgewise between blocks thereby'oiiering but little obstruction to flow of air through the unit; said elements having means distributed over their said edges for engaging fibres of the blocks, constitutingl supports against movement of those bres in directions transverse to the direction of iiow of air through the unit. f

'7. An air-filter unit, comprising brous filtering material organized in a plurality of masses of fibre in the shape of blocks, in each of which blocks the fibres extend across the direction of iiow of air through the unit, and are loosely matted to a substantial thickness of block in the said direction of 110W of air; means for maintaining the blocks spaced apart a substantial distance in the said direction of flow of air, said means comprising thin sheet elements set edge- Wise between blocks thereby offering but little obstruction to iiow of air through the unit; said elements having impaling points distributed along their said edges for impaling fibres at the surface of a block, thereby distributively supporting the fibre against movement in directions transverse to the direction of flow of air through the unit.

8. An air filter unit, comprising fibrous filtering material organized in a plurality of masses of f fibre in the shape of blocks, in each of which blocks the fibres extend across the direction of fiow of air through the unit, and are loosely matted to a substantial thickness of block in the said direction of iiow of air; means for maintaining the blocks spaced apart a substantial distance in the said direction of ow of air, said means comprising thin sheet elements set edgewise between blocks thereby oiiering but little obstruction to flow of air through the unit; said elements having an adhesive substance distributed over their edges for engaging fibres and providing distributed support for the fibre against movement in directions transverse to the direction of flow of air through the unit.

9. An air filter unit, comprising fibrous filtering material organized in a plurality of masses of fibre in the shape of blocks, in each of which blocks the fibres extend across the direction of flow of air through the unit, and are loosely matted to\a substantial thickness of block in the said direction of iiow of air; means for maintaining thefblocks spaced apart a substantial distance in the said direction of flow of air, said means comprising thinsheet elements crossing each other between the blocks and set edgewise thereby offering but little obstruction to flow of air through the unit.

10. An air filter unit, comprising fibres organized in a plurality of masses in the shape of blocks, in each of which blocks the fibres extend approximately parallel to the face of; the block,-

thus lying across the direction oi iicw of air through the unit, and are loosely matted in a substantial thickness of block in the said direction of air flow; combined with a plurality of thin strip elements, each being parallel-sided and having its edges extending in directions which 'are parallel to each other and to the faces of said blocks of bre, each strip being set edgewise toward the face of the block, with its width extending in direction perpendicular to the faces of said blocks of fibre, and each strip having width several times as great as its thickness, for spacing theblocks apart a distance approximating the width of said strip elements in the direction of flow of air; some of said strip elements having their broad faces upward and constituting floors for settling chambers between said blocks; the said fibres being long hard vegetable fibres, and the strip elements being distributed at intervals across an area parallel to the face of the block.

. RALPH L. DREW.

STEPHEN A. REED. 

